tests: Trim .nim files trailing whitespace

via OSX: find . -name '*.nim' -exec sed -i '' -E 's/[[:space:]]+$//' {} +

tests/misc/tinout.nim

@@ -3,14 +3,14 @@ discard """
   line: 12
   errormsg: "type mismatch: got (int literal(3))"
 """
-# Test in out checking for parameters
-
-proc abc(x: var int) =
-    x = 0
-
-proc b() =
-    abc(3) #ERROR
-
-b()
+# Test in out checking for parameters
+
+proc abc(x: var int) =
+    x = 0
+
+proc b() =
+    abc(3) #ERROR
+
+b()